Whatever you think this movie's going to be, you're wrong. Instead it's a lot of things, all happening at once. If you go in with that understanding, you'll probably like it.
The performances are great, which is good, because without that, this film would be hard to love. The story winds around a lot before it gets to the point, then winds around some more after it gets to the point. I had no problems with this, because the characters are so well written and played that it was worthwhile just being in their (rather surrealistic) space.
Basically it's an art film, except not annoying. The main characters don't take themselves too seriously, and although the screenplay touches on plenty of "heavy" themes, nobody drones on about them in black-and-white Swedish.
Like all art films it's also packed full of symbols, and it's kind of fun spotting and pondering them. I suspect when I see it again in a few years I'll catch more, and a few plot points that breezed past me the first time.
Basically, it's a friendly practical joke that leaves you thoughtful, and little happy and sad at the same time. As an essay on life, that's pretty dead-on.
Good movie to see with someone you like to talk with.